Dreaded VP Fuel Pump Whine

[ESGWheel]

How I dealt (so far) with dredged VP Fuel Pump Whine. 2005 Larson with a VP 5.0 GXi. New to me in 2015. Nice boat, well cared for, very low hours (less the 250).

My first encounter with the dreaded Fuel Pump Whine (FPW) was in 2017 when I noticed the unusual high pitched noise and started investigating. Using a mechanics stethoscope was not hard to figure out from the high pressure fuel pump and wow was it running hot!

With limited time and a strong desire to not break down during the season, my limited research reviled the aspect of the pump’s internal paint peeling which clogs the High Pressure Pump filter causing the whine and overheating. And that the Fuel Module cannot be rebuilt. So a $1,000 later I had my new OEM VP Fuel Module installed, checked the pressures (all good) and forgot about it. My mistake was not doing enough research.

Fast forward to 2019 and during our Northeastern limited boating season I hear that dreaded whine again. Quick investigation and yep, it was the FPW and the high pressure pump was hot to the touch. Crap. Lots more research this time and man oh man, lots of info about these Carter built pumps and how the ethanol gas dissolves the paint and they can be rebuilt, and, and, and….

Also during this time I was noticing a drop off in fuel mileage. Used to be an average of about 4 MPG and now down to 3 and even less. Note: I have a marine GPS so have accurate distance traveled and a fuel whistle in the vent tube which allows consistently filling the tank to the same level (the whistle is in the vent line and stops whistling when gas hits it). But I did not put 2 and 2 together about the mileage and FPW.

Not wanting to drop another grand only to do it again in a couple of years as well as not risk ending the boating season early, I opted for an aftermarket Fuel Assembly for $180 and started carrying it with all the necessary tools. Also signed up for BoatUS towing service. All cheap insurance and well worth the peace of mind. Boating season continued and in the meantime kept digging on what is the complete answer, if any.

Searching for posts on poor fuel mileage I ran across an excellent post by JohnnyCake of Helsinki, Finland back in 2015 about how he was experiencing poor mileage on his VP 5.0 GXi and traced it abnormally high fuel pressure due to a clogged return screed on the fuel pressure regulator. He even had a link to a VP Bulletin explaining how the screen should be replaced with an E-clip. And the screen was clogged due to dissolving paint!

A check of my pressures and sure enough high side running at 100 PSI vs. should be 50 to 60.

But here we go again with the VP parts so much more than anyone else. Come-on, I know this is a GM motor and not a VP specific design. Who has done the x-referencing? Fortunately many. So in goes a $30 generic regulator (supposedly a GM brand but no evidence of this anywhere on packaging), with screen, and poof, pressure down to 58 PSI and mileage back up to about 4 mpg. And boy oh boy was the other screen clogged with debris, I mean completely caked with crap. Was it paint? No doubt in my mind. E-clip? Not widely available but fortunately found it on eBay and got one to install later.

During some relaxing time on the boat I continued to search for the paint resolution. Ran across a video by Troy Brya from ManCaveMechanic who said he pulls the Fuel Modules apart, cleans out the internal paint, does what else is needed and puts it all back together. Hmmm, seems like the answer to the dreaded FPW and more. Fired off a quick email and sure enough he is still doing it.

In the meantime, got the E-Clip and read about how a BOSCH brand regulator fits in the VP 5.0 (and more) engines. Rather have a branded name so ordered on of those, also for $30. When it arrived I compared it to the VP OEM regulator with a Digital Caliper and was the same. Removed the screen and put on the E-clip, but more on that later.

So the plan is to compete the season, which is coming rapidly, and pull off my $1,000 OEM Fuel Module and send it to Tory of ManCaveMechanic for a rebuild that includes stripping the internal paint. Get it back installed, put in the BOSCH regulator, and then winterize it. The $180 aftermarket Fuel Assembly and ‘GM’ regulator? I’ll hang onto them, just in case. Along with the tow insurance.

I’ll follow up next season with an after action report on how it all played out.

Hope this is useful to someone with a 'new to them' but older boat with similar symptoms.

In the meantime here are some links that may be useful:

Troy Brya from ManCaveMechanic LLC who rebuilds VP Fuel Modules
http://youtu.be/udFyawGJL4I

Post about High Fuel Pressure by JonnyCake of Helsinki, Finland
https://rinkerboats.vanillacommuniti...ulletin-p-23-7

Aftermarket Fuel Module from Amazon (I have not installed this so cannot attest to its compatibility, etc.)
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

Aftermarket (GM brand?) Fuel Pressure Regulator from Amazon (it does work and does not leak)
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

BOSCH brand Fuel Pressure Regulator from Amazon (I have not installed this so cannot attest to its compatibility, etc. but it measures same as OEM)
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

E-clip (brand unknown due to generic packaging) from eBay (it did install correctly per the VP Bulletin but I have not installed the assembly yet)
https://www.ebay.com/itm/VOLVO-PENTA...72.m2749.l2649

VP E-Clip Bulletin
https://www.dropbox.com/s/i3y1kznhp9btg7g/156%20PB%20P-23-7%20N03%20V01%20Fuel%20Pressure%20Regulator.pdf?dl=0

 

[Ironman888]

Good info. I have a new to me 2001 5.0 GXI and the previous owner supposedly replaced the pump assembly in the last few years. It seems to be holding up for now. I’ll check back once you update.

 

[stang32]

wow, now thats an informative post, thanks .
i just did a new fp in a 2006 5.7. now im dealing with a stumbling issue and im thinking i should check that reguator screen.

 

[ESGWheel]

Trying to post some pics of the E-clip install but cannot...
I've read thru the "how to" post but all direct methods not working...

Here is the write up:

Here is the E-clip follow up:

As mentioned above, I bought a BOSCH Fuel Pressure Regulator, Part No. 0280160575 for $30 based on some other reviews that said it was a perfect match for the VP Fuel Pressure Regulator, Part No. 3858967 which lists for $258 at the VP Store (and is currently out of stock) but can be found from various retailers for $85. The VP Regulator 3858967 is common on (most?) of the Red Engines 4.3, 5.0 and 5.7. And the BOSCH has the same pressure setting as OEM at 400kPa which is 58 PSI. Note the BOSCH regulator is imprinted with “400kPa”. Also got an E-clip per the P-23-7-3 Bulletin, links above.

The Bulletin procedure says “Gently pry the fuel screen off of the regulator.” Followed by “Do not damage the o-rings or spacer when removing the screen.”

Yeah, right.

The design of the regulator is such that the screen goes on over a ‘one-way’ shoulder. See mock up below of what that looks like. Also the hole diameter of the screen where it slips over the regulator is sized perfectly for the regulator, meaning slipping it over the protruding O-ring without damaging it would be near impossible.

Anticipating I would have to remove the O-Rings and potentially damage them I sought out getting replacements. However these are sold as a ‘kit’ with all the seals for the Injectors at a cost ranging from $40 to $170. A couple of emails to the eBay sellers and was able to get the 2 needed O-rings at a reasonable cost.

Experimenting with the removed VP Regulator I pulled the smaller O-ring off and it became clear no way to get that screen over the shoulder. And damage to the larger O-ring and its Spacer seemed certain if using a pry tool. OK, new approach. What if I broke apart the screen? At first gently, and then with more and more force, prying my fingers under the screen in the remove direction it broke around the small hole. Since the majority of the screen is screen I was able to use a small pair of needle nose pliers to widen up the hole and easily slip it off. Think in terms of a lock washer and opening up its hole by bending up and back one of the ends. See picture of broken screen. Emboldened with this technique I set about to remove the screen on the BOSCH. However I did not remove the smaller O-ring. The screen broke in the same manner and I was able to easily remove it with the needle nose pliers being careful to avoid the O-ring with any sharp broken edge of the screen.

Installing the E-clip was done by fitting it partially on it groove (see mock up) and then using a scrap piece of wood I pressed down on the back of the E-clip and got it to snap on. See picture showing how this was done.

I have not installed this BOSCH Regulator so cannot yet attest to its working; that will be next season.

But this process works for installing the E-clip on whichever regulator you choose.

 

[ESGWheel]

Update: opening of the 2020 season.

Was not even sure we would have a season with the COVID situation. Fortunately we have not been impacted health wise. And also fortunately we were able to get out boat in for the last few weekends. Nice get away from all the shelter in place.

OK so what has been the initial result of the rebuilt pump and Bosch pressure regulator with E-Clip?

FANTASTIC is the word that comes to mind. Previously my WOT gets 5,000 RPM and about 44.5 MPH (have GPS onboard). And I have done a lot of WOT throughout the years. Always 5k as I purposely prop'ed it that way and it’s the supposed RPM limit on these 5.0 motors. And always around 44.2 to 44.7, trimmed out, full tank, 2 people aboard. Boy was I surprised to get to 5,200 and 47 MPH! Wait that must be wrong. Let's try again. Yep, 5.2k and 47.3. Hmm... So the next weekend, again and yep, still at 5,200 and slightly above 47.

I forgot to take along my fuel pressure gauge to see what both the low and high pressures are. I post those numbers at a future date.

So if you have an OEM pump assembly, IMO there is only one thing to do: get the paint scrapped out of it and install a new regulator with the E-clip.

Oh, and it looks like i can post pics now, so here are the ones showing the OEM and Bosch Regulators as mentioned in my previous post.

 

[Coreykuhl]

My fuel pump left me dead I’m the water a couple years ago. I replaced the high pressure pump and it went well for a season and then began whining last season, and then this season it whined, got super hot and wants to stall when I try to accelerate. So I replaced the high pressure pump again…. Still won’t accelerate and dies… all while getting hot Again. I checked the pickup line in the fuel tank.. checkout okay, knocked the anti cyphen valve out to ensure no performance issues there… still gets hot on the driveway on hose water. So I just replaced my entire VST pump assembly after going through two high pressure pumps in three years. The new VP assembly came with low pressure and high pressure pumps and new fuel filter. $1500. Fought with it for a few hours and finally got it all sorted and hooked up the water, primed it several times and started right up… after a couple of min the high pressure pump is hot to the touch again. Wtf? I am guessing it’s the fuel pressure regulator at this point. I am going to check the pressure on the fuel rail in the morning. What’s the deal with the e-clip?

 

[Coreykuhl]

Update:
My fuel rail was at 64psi and maintained that through idle and accelerating… low pressure was constant at 16psi, the HP pump was cool today the whole time running it? Only thing different was I took the fuel pump regulator off last night and blew on it and tapped it on the deck to get any debris off… didn’t appear that much of anything came off, but now my pump is running cool! I don’t know? Any thoughts? I am taking her out this afternoon to see how she does under a load

 

[Coreykuhl]

Update:
My fuel rail was at 64psi and maintained that through idle and accelerating… low pressure was constant at 16psi, the HP pump was cool today the whole time running it? Only thing different was I took the fuel pump regulator off last night and blew on it and tapped it on the deck to get any debris off… didn’t appear that much of anything came off, but now my pump is running cool! I don’t know? Any thoughts? I am taking her out this afternoon to see how she does under a load

2nd update, I decided to take the FPR off and thoroughly clean it with carb cleaner and compressed air… lots of debris came off. The fuel rail pressure dropped from 64-65psi to 52psi. Pump stayed cool and the boat ran like a top! Very responsive throttle…